There is more and more discussion among arborists regarding preserving “old” trees. Many are concerned that these “over-mature” trees, with their dead branches and open cavities, pose a threat to people nearby. Others argue that these “veteran trees” as they are referred to in Europe, or “wolf trees” in the American lexicon, provide valuable and irreplaceable ecological benefits. We are talking about 100 to 300 hundred and even 500 year old trees here. Everyone recognizes the antiquity of the redwoods and bristle cone pines out west, but many of these veteran, or wolf trees, reside right here with us in New England, some outdating the birth of our nation. We need to learn to recognize these trees for what they are and not as just some old tree that should be removed. Here is an interesting article about “wolf trees” in our forests, but you should recognize that many of these trees also exist in our own back yards. Before you decide to just kill that old tree on your property, you should consult with an ASCA Consulting Arborist to discuss your options and just maybe save hundreds of years worth of history and a habitat that can’t be recreated for centuries to come.
You may have noticed that many the spruce trees in our area of southern New England have been dying lately. The cause is a fungal disease called Rhizosphaera needle cast. Like most needle cast diseases, Rhizosphaera infects the newly emerging needles of its host trees from older needles infected the previous year. The newly infected needles will grow normally through the current growing season and will not show signs of infection until the fungus matures to its spore producing stage, usually late winter or early spring of the following year, but sometimes as early as late fall of the current growing season. As you can see in the photograph below, the disease typically affects the lower portions of the tree first and progresses farther up the tree in subsequent years until the tree dies.
Not all spruce trees are equally susceptible to infection by Rhizosphaera. Colorado spruce (Picea pungens) is most susceptible. White spruce (Picea glauca) is somewhat susceptible and Norway spruce (Picea abies) very resistant to infection. Trees stressed by drought, poor cultural practices are more susceptible than healthy, vigorous trees.
Trees infected with Rhizosphaera can be effectively treated with well timed, preventive fungicide applications if the disease is caught early enough. Spruce trees typically retain three to five years worth of older needles that they need to photosynthesize enough food to maintain growth. Rhizosphaera kills the trees by causing these older needles to fall prematurely, slowly starving the tree. It may take several years of treatment to regenerate a full compliment of needles until the tree looks full and healthy again.
To learn more about Rhizosphaera needle cast, contact us or visit these websites:
Invasive plant species are a problem that can have a serious impact on our local ecosystems. The Massachusetts Invasive Plant Advisory Group [MIPAG] defines invasive plants as “non-native species that have spread into native or minimally managed plant systems in Massachusetts, causing economic or environmental harm by developing self-sustaining populations and becoming dominant and/or disruptive to those systems.” According to the New England Wild Flower Society, “seventy-nine species [of invasive plants] cost the U.S. economy more than $97 billion annually in lost crops, failed recovery efforts for endangered species, and control efforts. Invasive species have contributed to the decline of 42% of U.S. endangered and threatened species; for 18% of U.S. endangered or threatened species, invasives are the main cause of decline.”
Invasive plants decrease biodiversity and displace native species that wildlife depend upon for food and cover. For example, bush honeysuckle (Lonicera s.pp.) creates dense stands that exclude native plant species. The fruits, produced from mid-summer through early fall, are very attractive to birds. While the fruits are rich in carbohydrates, they lack the fat and nutrient content to sustain migrating birds on their long journeys south; they are essentially junk food for birds. Because the dense stands of honeysuckle exclude the nutritious native plants, they become the dominant fodder for migrating birds at a time when they need to foraging on nutritious food for their trip south the most.
In most cases, it is not practical to completely eliminate invasive plants from your community, but you can create pockets of invasive free areas on your own property. First, identify invasives on your property. Spring and fall are good times to look for invasives; most of the understory invasive shrubs leaf out first in the spring and drop their leaves last.
Of course there are many other invasive plant species you may want to familiarize yourself with and explore the various options for controlling them, including mechanical methods such as hand pulling them or chemical controls. Here are just a few of the many websites you can visit to learn more about invasive plants and how to control them:
Massachusetts Invasive Plant Advisory Group http://www.massnrc.org/MIPAG/index.htm#contacts
Audubon Connecticut http://ct.audubon.org/remove-invasive-plants
New England Wild Flower Society http://www.newfs.org/about
RI Invasive Species Council http://rinhs.org/invasive-species-portal/riisc/
The Invasive Plant Atlas of New England’s (IPANE) http://www.eddmaps.org/ipane/index.html
Pennsylvania DCNR http://www.dcnr.state.pa.us/forestry/plants/invasiveplants/index.htm
Well, I for one have had enough of the 2013-2014 winter season. Its March 13 and its snowing. Again. But this brutally cold winter season may have some beneficial side effects. In a March 2, 2014 Worcester Sunday Telegram report, University of Massachusetts-Amherst Professor Joseph Elkinton notes that the extreme cold, down to 15 degrees below zero F in the Amherst area, will likely result in a large die-off of the Hemlock Wooly Adelgid, a non-native invasive insect pest that has devastated our hemlock forests and is a serious pest of hemlocks in our landscapes. In the same article, Kenneth Gooch, Forest Health Program supervisor for the Department of Conservation and Recreation is optimistic, noting that the last time we had temperatures this cold, adelgid mortality reached 80%. Keep in mind, however, that the reprieve is temporary. The adelgids that do survive will eventually rebound, and may produce offspring genetically more resistant to cold temperatures. And while I did not experience temperatures as cold as Professor Elkinton reported here in southern Worcester County or Windham County, we did have several nights of below zero temperatures, and some adelgid mortality results at temperatures as “warm” as 5 degrees F.
As much as I hate to admit it, we have had it easy here in New England. The folks in the Midwest really got frosted and the south was exceptionally cold. But again, more potential good news. The Week magazine reports that the cold has killed 80% of the Emerald Ash Borer, another non-native invasive insect that has killed tens of millions of ash trees in the Midwest and has now been found in New Haven County, CT, western Massachusetts and North Andover, MA, and New Hampshire. The Week also reports that large percentages of Gypsy Moths, Hemlock Wooly Adelgid, Corn Earworm, and the citrus destroying Cottony Cushion Scale have been killed off by the cold.
I don’t expect this to be the end of our problems with these invasive pests, but its comforting to know that some good can come from our having to endure the winter of 2013-2014.
Here is an interesting tree we recently removed in Webster, MA. The owner was concerned about the large split that had propagated up the lower trunk in the photo below.
The pronounced swelling at the base of the tree caught my attention. This is often a sign of a root rot progressing up into the lower trunk. The tree “senses” the weakness in its trunk and adds extra growth to that area to shore itself up. You can see in the photo of the overturned stump after we cut the tree down, where the root rot has decayed the center of the tree and where the tree added new sound wood around the perimeter of the stump in an attempt to preserve itself. Unfortunately, the decay had progressed about ten feet up into the trunk, leading to the crack opening up in a wind event, requiring the removal of the tree.
Well, its snowing AGAIN here in Thompson, CT. Cabin fever is setting in. But for those of you planning your fruit crops for the coming year, there is hope. Here is a link to the UMass Extension’s Cold Spring Orchard. http://extension.umass.edu/fruitadvisor/ and the Fruit Adviser web page https://extension.umass.edu/fruitadvisor/fact-sheets. You’ll find useful information information on everything from selecting good apple varieties to plant in New England to how to prune your raspberries. So start boning up; spring will be here before you know it!
With the recent rains we have received, its easy to forget how hot and dry it was this summer in the Northeast. Now that the fall rains have arrived, problem solved, right? Well, drought damages trees, and simply returning to a regular rainfall pattern after drought damage has occurred is not enough. The trees need a chance to recover from drought conditions. I have reprinted some recommendations from the University of Massachusetts Extension Service’s Landscape Message at: http://extension.umass.edu/landscape/message/lm-202012 below.
Will the Fall Rains be Enough?
With the start of September, we begin to look back on what was the summer of 2012. As of the end of August, the National Drought Mitigation Center’s Drought Monitor (http://drought.unl.edu) classified the entire state of Massachusetts as being “abnormally dry” (D0) with regards to rainfall totals, with a significant amount of the Commonwealth actually being in a “moderate” state of drought (D1). While there are other areas of the nation in a much more severe state of drought (parts of the high plains and Midwest are considered “D4” or in an “extreme” state, likened to that of the Dustbowl Era) than we are here in the Northeast, there remain some important considerations as it relates to the environment – and of course the trees – around us. And since we know that growing seasons are not isolated, we must keep in mind that the effects of this season’s rain shortage will be a furtherance of the serious stress event that our trees experienced in the summer of 2010 – the hottest growing season on record in the Northeast that offered up less than 50% of our normal rainfall!
So, whether we care for miles of streets and acres of parks populated with trees or one important specimen on a client’s property, the question remains: what do we do?
- Priority attention should be given to new plantings and drought-sensitive species like ornamental cherries (Prunus spp.), certain maples (Acer saccharum, Acer palmatum), eastern hemlock (Tsuga canadensis), katsura (Cercidiphyllum japonicum), yellowwood (Cladrastis kentukea) and amelanchier (Amelanchier spp.).
- Water – our most important weapon in the battle against drought stress – should be administered slowly, like a steady rainfall. The use of a gator bag (a perforated, synthetic bag that disseminates an even flow of water) on trees aids this process tremendously, as may the use of a drip irrigation system. Additionally, in drought-like conditions, administering supplemental water to new plantings that are in a site for up to 5 years (depending on the specimen and site conditions) may be necessary AND it may be necessary to extend the supplemental watering period into the fall months (October).
- Common tree maintenance activities (like pruning and fertilizing) should only be implemented selectively, in very specific situations – if at all, when under drought conditions.
- Since we know that both allelopathic-generated antagonism from certain turfgrass species AND competition for resources like water and nutrients with other plants can be a detriment to tree root populations, we need to make sure that vegetation within the vicinity of the base of the tree is not present as a competitive factor.
- Researchers and practitioners alike have long advocated the use of 2-3 inches of mulch around the base of trees (but not contacting the actual stem) as another important method to help preserve soil moisture in the vicinity of the tree roots.
- Monitoring trees both while they are being watered (this includes sampling the soil around the tree at a depth of 12-18″ to make sure that proper moisture penetration is occurring) and after they have been “nursed through” a tough growing season is a critical. Canopy thining and premature leaf drop in following seasons are symptoms that may indicate that the tree continues to suffer the effects of a drought event.
- Additionally, certain insect and disease pests of importance may be more attracted to a tree that has been stressed by an event such as drought. These factors combine to make routine inspections – and good record keeping – even more important.
These recommendations are equally, if not more important for mature trees during and after drought conditions, because mature trees are less resilient once drought stress occurs.
Most people believe that mature trees have extensive, deep root systems and they never need supplemental watering. Nothing could be further from the truth. If you truly love your trees, water them!
One thing I forgot to mention in my last post on the discovery of Emerald Ash Borer (EAB) in Connecticut is how it was discovered. The conventional method of detecting most insects is to deploy pheromone sticky traps to attract them. The EAB traps in use have been dubbed “Barney Traps” because they are big and purple like the dinosaur. The traps attract the beetles by emitting a pheromone “scent” with the promise of meeting a mate. What could be more ingenious than that?
Well how about this: Claire E. Rutledge, Assistant Entomologist at the Connecticut Agricultural Experiment Station has been studying boring insects for a long time. She not only studies the insects themselves, but their ecology as well. It turns out that there is a native wasp that hunts native Buprestid beetles, the family that the EAB belongs to. Her research indicated that they would hunt EAB as well. Ms. Rutledge and a group of volunteers, monitoring the wasps’ nesting sites, detected the wasp, Cerceris fumipennis, returning to their nests with EAB that they had captured in the nearly impossible to monitor tree canopies with the invasive beetle. Now that’s innovation!
It’s research like this that make our Connecticut Agricultural Experiment Station and all state Cooperative Extension Service offices so valuable to all of us. They are always there with an eye out on our natural resources. Recent budget cuts have threatened many of these information outlets. Please support them when you can.
Invasive pests continue to be a problem in the Northeast. Hemlock Wooly Adelgid has been decimating our hemlock forests for years, and we have been battling the Asian Longhorned Beetle in the Worcester, Massachusetts area since its discovery there in 2008. Emerald Ash Borer (Agrilus planipennis Fairmaire), an invasive insect native to Asia, has killed tens of millions of ash trees in urban, rural and forested settings. This beetle was first discovered in 2002 in southeast Michigan and Windsor, Ontario. We have kept a close eye on this pest as it approached the western borders of Connecticut and Massachusetts, crossing the Hudson River in New York in April of this year. This week, word was sent out that the Emerald Ash Borer has been detected in Connecticut. At this point we should begin to consider protecting the valuable ash trees on our properties. Unless you are in the immediate area of infestation (New Haven County) we still have some time to plan and develop an effective preventive program to preserve our ash trees. Please visit this website for more information how to protect your trees: http://www.emeraldashborer.info/
I am often asked to predict if a tree will fail, but to be honest, no one can really predict when and how a tree will fail. Case in point: I had a client in Pomfret, CT who had two sugar maples (Acer saccharum) standing sentinel at either side of the end of her driveway. The tree top the left was so severely decayed I couldn’t figure out how it was still standing. The tree on the right side was in good health and perfectly sound. Every time I visited the site I would tell her that she should take the tree down before it just falls. After five years, I finally got the call I had been waiting for; “Dennis, my maple tree fell during the storm last night.” My reply? “I told you so.” Her response? “No, no, the good tree fell!”
The white ash (Fraxinus Americana) stump in Sturbridge, MA pictured here is another example of the difficulty in predicting tree failures. Grinding the stump after removing what remained of the tree revealed extensive root decay. Had I examined the tree before it failed, I would have expected the tree to tip out of the ground in a wind storm because so much of the root system had rotted away. What actually happened is the top of the tree was twisted right off in the June 1, 2011 Tornado.
While these examples may leave us with egg on our face, we are still pretty good at associating recognizable conditions with higher probabilities of failures and the failure patterns associated with those conditions. I can’t tell you the exact time a tree will fail or the conditions that will precipitate that failure, but when that time comes, more often than not, that tree will fail as a result of a recognizable condition such as a weak fork, decayed trunk, or a compromised root system.